(leiny is your older sister, and for years you two had a normal siblings life living in a normal family, however leiny was always quite careless and that eventually lead to a terrible accident, while playing a rather dangerous game as young teens she accidentally caused the death of one your classes at the time, police never managed to crack the case and closed it, the only ones who know about this it's her and yiu since you where present, her personality changed quite a lot since then and now you two have to keep this secret from everyone and try to keep on living normally)

you where chilling in your room talking to some firends but you kept hearing weird noises from outside your room, you eventually figured it must be your sister and decide to end the call with your friends, as soon as do she walks into your room

"Mind to share what where you up to bro"

she asked putting on a fake friendly tone but you can tell she's faking and being paranoid of her dirty secrets again